Turbine engine blade made of composite material, and a method of fabricating it

Abstract

A turbine engine blade made of composite material including fiber reinforcement densified by a matrix is fabricated by a method including: performing three-dimensional weaving to make a single-piece fiber blank; shaping the fiber blank to obtain a single-piece fiber preform having a first portion forming a preform for a blade root and an airfoil, at least one second portion forming a preform for a blade inner platform or for wipers of a blade outer platform, and at least one third portion forming a preform for reinforcing a blade inner platform or for overhangs of a blade outer platform; and densifying the fiber preform with a matrix to obtain a composite material blade having fiber reinforcement constituted by the preform and densified by the matrix, and forming a single piece with an inner and/or outer platform incorporated therein.

The invention claimed is: 
     
       1. A method of fabricating a turbine engine blade out of composite material comprising fiber reinforcement densified by a matrix, the method comprising:
 performing three-dimensional weaving to make a single-piece fiber blank; 
 shaping the fiber blank to obtain a single-piece fiber preform having a first portion forming a preform for a blade root and an airfoil, at a second portion forming a preform for a blade inner platform or for wipers of a blade outer platform, and a third portion forming a preform for reinforcing a blade inner platform or for an overhang of a blade outer platform; and 
 densifying the fiber preform with a matrix to obtain a composite material blade having fiber reinforcement constituted by the preform and densified by the matrix, and forming a single piece with at least one of an inner platform and an outer platform incorporated therein, 
 wherein, in a longitudinal direction corresponding to a longitudinal direction of the fiber blank that is to be fabricated, the fiber blank comprises:
 a first set of a plurality of yarn layers that are linked together to form the first portion of the blank corresponding to the blade root and airfoil preform; 
 a second set of a plurality of yarn layers that are linked together at least locally to form at least the second portion of the blank corresponding to the blade inner platform preform or to the blade outer wiper preform; and 
 a third set of a plurality of yarn layers that are linked together at least locally to form the third portion of the blank corresponding to the blade inner platform reinforcement preform or to the blade outer platform overhang preform; 
 
 wherein the yarns of the first set of yarn layers are not linked with the yarns of the second and third sets of yarn layers; and 
 wherein the first set of yarn layers has yarns of the second and third sets of yarn layers crossing through the second portion of the fiber blank and through the third portion of the fiber blank. 
 
     
     
       2. A method according to  claim 1 , wherein the fiber blank is woven with second and third continuous sets of yarn layers and shaping of the fiber blank includes eliminating portions of the second and third sets of yarn layers that lie outside the second fiber blank portion and the third fiber blank portion by cutting said portions of the second and third sets of yarn layers off. 
     
     
       3. A method according to  claim 1 , wherein the second and third sets of yarn layers cross through the first set of yarn layers in a same direction. 
     
     
       4. A method according to  claim 1 , wherein the second and third sets of yarn layers cross through the first set of yarn layers in opposite directions. 
     
     
       5. A method according to  claim 1 , wherein, in the first portion of the fiber blank and in a direction that corresponds to a direction along which a profile of a varying-thickness airfoil extends in the blade that is to be fabricated, the number of yarn layers in the first set of yarn layers is constant. 
     
     
       6. A method according to  claim 5 , wherein the yarns of the first set of yarn layers are of varying weight. 
     
     
       7. A method according to  claim 5 , wherein thread count of the yarns of the first set of yarn layers varies. 
     
     
       8. A method according to  claim 1 , wherein three-dimensional weaving is used to make a strip comprising a succession of fiber blanks. 
     
     
       9. A method according to  claim 1 , wherein the blanks are woven with the longitudinal direction that corresponds to a direction of the blades that are to be fabricated extending in a weft direction. 
     
     
       10. A method according to  claim 1 , wherein the blanks are woven with the longitudinal direction that corresponds to a direction of the blades that are to be fabricated extending in a warp direction. 
     
     
       11. A turbine engine fitted with at least one blade fabricated using the method of  claim 1 . 
     
     
       12. A turbine engine blade made of composite material comprising fiber reinforcement obtained by three-dimensional weaving of yarns and densified by a matrix, the blade comprising:
 a first portion constituting a root and airfoil of the blade and that is formed integrally with: 
 a second portion constituting a blade inner platform or wipers of a blade outer platform; and 
 a third portion constituting inner platform reinforcement or a preform for overhangs of a blade outer platform; 
 the fiber reinforcement portions corresponding to the first, second, and third blade portions being mutually interleaved at least in part with yarns of the first portion of the fiber reinforcement penetrating into the second portion of the fiber reinforcement, 
 wherein the yarns constituting the portion of the fiber reinforcement that corresponds to the first portion of the blade are not linked with the yarns constituting the portion of the fiber reinforcement that corresponds to the second and third portions of the blade, and 
 wherein the yarns constituting the portion of the fiber reinforcement that corresponds to the second and third portions of the blade cross through the portion of the fiber reinforcement that corresponds to the first portion of the blade. 
 
     
     
       13. A blade according to  claim 12 , made of ceramic matrix composite material. 
     
     
       14. A blade according to  claim 12 , wherein the blade airfoil has a profile of varying thickness along which the fiber reinforcement portion corresponding to the first blade portion includes, in a longitudinal direction of the blade, a constant number of layers of yarns that are of varying of at least one of weight and thread count. 
     
     
       15. A blade according to  claim 12 , wherein the blade airfoil has a profile of varying thickness along which the fiber reinforcement portion corresponding to the first portion of the blade has a varying number of yarn layers extending in a longitudinal direction of the blade. 
     
     
       16. A turbine engine fitted with at least one blade according to  claim 12 .